1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // Format list-like macro invocations. These are invocations whose token trees
12 // can be interpreted as expressions and separated by commas.
13 // Note that these token trees do not actually have to be interpreted as
14 // expressions by the compiler. An example of an invocation we would reformat is
15 // foo!( x, y, z ). The token x may represent an identifier in the code, but we
16 // interpreted as an expression.
17 // Macro uses which are not-list like, such as bar!(key => val), will not be
19 // List-like invocations with parentheses will be formatted as function calls,
20 // and those with brackets will be formatted as array literals.
22 use std::collections::HashMap;
25 use syntax::codemap::{BytePos, Span};
26 use syntax::parse::new_parser_from_tts;
27 use syntax::parse::parser::Parser;
28 use syntax::parse::token::{BinOpToken, DelimToken, Token};
29 use syntax::print::pprust;
31 use syntax::tokenstream::{Cursor, ThinTokenStream, TokenStream, TokenTree};
32 use syntax::util::ThinVec;
33 use syntax::{ast, ptr};
35 use codemap::SpanUtils;
37 contains_comment, remove_trailing_white_spaces, CharClasses, FindUncommented, FullCodeCharKind,
40 use expr::rewrite_array;
41 use lists::{itemize_list, write_list, ListFormatting};
43 use rewrite::{Rewrite, RewriteContext};
44 use shape::{Indent, Shape};
46 use utils::{format_visibility, mk_sp, wrap_str};
48 const FORCED_BRACKET_MACROS: &[&str] = &["vec!"];
50 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
51 pub enum MacroPosition {
60 Expr(ptr::P<ast::Expr>),
62 Pat(ptr::P<ast::Pat>),
63 Item(ptr::P<ast::Item>),
66 impl Rewrite for ast::Item {
67 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
68 let mut visitor = ::visitor::FmtVisitor::from_context(context);
69 visitor.block_indent = shape.indent;
70 visitor.last_pos = self.span().lo();
71 visitor.visit_item(self);
76 impl Rewrite for MacroArg {
77 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
79 MacroArg::Expr(ref expr) => expr.rewrite(context, shape),
80 MacroArg::Ty(ref ty) => ty.rewrite(context, shape),
81 MacroArg::Pat(ref pat) => pat.rewrite(context, shape),
82 MacroArg::Item(ref item) => item.rewrite(context, shape),
87 fn parse_macro_arg(parser: &mut Parser) -> Option<MacroArg> {
88 macro_rules! parse_macro_arg {
89 ($macro_arg:ident, $parser:ident, $f:expr) => {
90 let mut cloned_parser = (*parser).clone();
91 match cloned_parser.$parser() {
93 if parser.sess.span_diagnostic.has_errors() {
94 parser.sess.span_diagnostic.reset_err_count();
97 *parser = cloned_parser;
98 return Some(MacroArg::$macro_arg($f(x)?));
103 parser.sess.span_diagnostic.reset_err_count();
109 parse_macro_arg!(Expr, parse_expr, |x: ptr::P<ast::Expr>| Some(x));
110 parse_macro_arg!(Ty, parse_ty, |x: ptr::P<ast::Ty>| Some(x));
111 parse_macro_arg!(Pat, parse_pat, |x: ptr::P<ast::Pat>| Some(x));
112 // `parse_item` returns `Option<ptr::P<ast::Item>>`.
113 parse_macro_arg!(Item, parse_item, |x: Option<ptr::P<ast::Item>>| x);
118 /// Rewrite macro name without using pretty-printer if possible.
119 fn rewrite_macro_name(path: &ast::Path, extra_ident: Option<ast::Ident>) -> String {
120 let name = if path.segments.len() == 1 {
121 // Avoid using pretty-printer in the common case.
122 format!("{}!", path.segments[0].ident)
127 Some(ident) if ident != symbol::keywords::Invalid.ident() => format!("{} {}", name, ident),
132 pub fn rewrite_macro(
134 extra_ident: Option<ast::Ident>,
135 context: &RewriteContext,
137 position: MacroPosition,
138 ) -> Option<String> {
139 context.inside_macro.replace(true);
140 let result = rewrite_macro_inner(mac, extra_ident, context, shape, position);
141 context.inside_macro.replace(false);
145 pub fn rewrite_macro_inner(
147 extra_ident: Option<ast::Ident>,
148 context: &RewriteContext,
150 position: MacroPosition,
151 ) -> Option<String> {
152 if context.config.use_try_shorthand() {
153 if let Some(expr) = convert_try_mac(mac, context) {
154 context.inside_macro.replace(false);
155 return expr.rewrite(context, shape);
159 let original_style = macro_style(mac, context);
161 let macro_name = rewrite_macro_name(&mac.node.path, extra_ident);
163 let style = if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
169 let ts: TokenStream = mac.node.stream();
170 let has_comment = contains_comment(context.snippet(mac.span));
171 if ts.is_empty() && !has_comment {
173 DelimToken::Paren if position == MacroPosition::Item => {
174 Some(format!("{}();", macro_name))
176 DelimToken::Paren => Some(format!("{}()", macro_name)),
177 DelimToken::Bracket => Some(format!("{}[]", macro_name)),
178 DelimToken::Brace => Some(format!("{}{{}}", macro_name)),
182 // Format well-known macros which cannot be parsed as a valid AST.
183 // TODO: Maybe add more macros?
184 if macro_name == "lazy_static!" && !has_comment {
185 if let success @ Some(..) = format_lazy_static(context, shape, &ts) {
190 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
191 let mut arg_vec = Vec::new();
192 let mut vec_with_semi = false;
193 let mut trailing_comma = false;
195 if DelimToken::Brace != style {
197 match parse_macro_arg(&mut parser) {
198 Some(arg) => arg_vec.push(arg),
199 None => return Some(context.snippet(mac.span).to_owned()),
206 // Try to parse `vec![expr; expr]`
207 if FORCED_BRACKET_MACROS.contains(&¯o_name[..]) {
209 if parser.token != Token::Eof {
210 match parse_macro_arg(&mut parser) {
214 if parser.token == Token::Eof && arg_vec.len() == 2 {
215 vec_with_semi = true;
219 None => return Some(context.snippet(mac.span).to_owned()),
223 return Some(context.snippet(mac.span).to_owned());
225 _ => return Some(context.snippet(mac.span).to_owned()),
230 if parser.token == Token::Eof {
231 trailing_comma = true;
238 DelimToken::Paren => {
239 // Format macro invocation as function call, preserve the trailing
240 // comma because not all macros support them.
241 overflow::rewrite_with_parens(
244 &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>(),
247 context.config.width_heuristics().fn_call_width,
249 Some(SeparatorTactic::Always)
251 Some(SeparatorTactic::Never)
253 ).map(|rw| match position {
254 MacroPosition::Item => format!("{};", rw),
258 DelimToken::Bracket => {
259 // Handle special case: `vec![expr; expr]`
261 let mac_shape = shape.offset_left(macro_name.len())?;
262 let (lbr, rbr) = if context.config.spaces_within_parens_and_brackets() {
268 let total_overhead = lbr.len() + rbr.len() + 6;
269 let nested_shape = mac_shape.block_indent(context.config.tab_spaces());
270 let lhs = arg_vec[0].rewrite(context, nested_shape)?;
271 let rhs = arg_vec[1].rewrite(context, nested_shape)?;
272 if !lhs.contains('\n')
273 && !rhs.contains('\n')
274 && lhs.len() + rhs.len() + total_overhead <= shape.width
276 Some(format!("{}{}{}; {}{}", macro_name, lbr, lhs, rhs, rbr))
282 nested_shape.indent.to_string_with_newline(context.config),
284 nested_shape.indent.to_string_with_newline(context.config),
286 shape.indent.to_string_with_newline(context.config),
291 // If we are rewriting `vec!` macro or other special macros,
292 // then we can rewrite this as an usual array literal.
293 // Otherwise, we must preserve the original existence of trailing comma.
294 let macro_name = ¯o_name.as_str();
295 let mut force_trailing_comma = if trailing_comma {
296 Some(SeparatorTactic::Always)
298 Some(SeparatorTactic::Never)
300 if FORCED_BRACKET_MACROS.contains(macro_name) {
301 context.inside_macro.replace(false);
302 if context.use_block_indent() {
303 force_trailing_comma = Some(SeparatorTactic::Vertical);
306 // Convert `MacroArg` into `ast::Expr`, as `rewrite_array` only accepts the latter.
307 let arg_vec = &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>();
308 let rewrite = rewrite_array(
314 force_trailing_comma,
315 Some(original_style),
317 let comma = match position {
318 MacroPosition::Item => ";",
322 Some(format!("{}{}", rewrite, comma))
325 DelimToken::Brace => {
326 // Skip macro invocations with braces, for now.
327 indent_macro_snippet(context, context.snippet(mac.span), shape.indent)
333 pub fn rewrite_macro_def(
334 context: &RewriteContext,
339 vis: &ast::Visibility,
341 ) -> Option<String> {
342 let snippet = Some(remove_trailing_white_spaces(context.snippet(span)));
343 if snippet.as_ref().map_or(true, |s| s.ends_with(';')) {
347 let mut parser = MacroParser::new(def.stream().into_trees());
348 let parsed_def = match parser.parse() {
350 None => return snippet,
353 let mut result = if def.legacy {
354 String::from("macro_rules!")
356 format!("{}macro", format_visibility(vis))
360 result += &ident.name.as_str();
362 let multi_branch_style = def.legacy || parsed_def.branches.len() != 1;
364 let arm_shape = if multi_branch_style {
366 .block_indent(context.config.tab_spaces())
367 .with_max_width(context.config)
372 let branch_items = itemize_list(
373 context.snippet_provider,
374 parsed_def.branches.iter(),
377 |branch| branch.span.lo(),
378 |branch| branch.span.hi(),
379 |branch| branch.rewrite(context, arm_shape, multi_branch_style),
380 context.snippet_provider.span_after(span, "{"),
383 ).collect::<Vec<_>>();
385 let fmt = ListFormatting {
386 tactic: DefinitiveListTactic::Vertical,
387 separator: if def.legacy { ";" } else { "" },
388 trailing_separator: SeparatorTactic::Always,
389 separator_place: SeparatorPlace::Back,
391 ends_with_newline: true,
392 preserve_newline: true,
393 config: context.config,
396 if multi_branch_style {
398 result += &arm_shape.indent.to_string_with_newline(context.config);
401 result += write_list(&branch_items, &fmt)?.as_str();
403 if multi_branch_style {
404 result += &indent.to_string_with_newline(context.config);
411 fn register_metavariable(
412 map: &mut HashMap<String, String>,
417 let mut new_name = String::new();
418 let mut old_name = String::new();
421 for _ in 0..(dollar_count - 1) {
426 new_name.push_str(&name);
427 old_name.push_str(&name);
429 result.push_str(&new_name);
430 map.insert(old_name, new_name);
433 // Replaces `$foo` with `zfoo`. We must check for name overlap to ensure we
434 // aren't causing problems.
435 // This should also work for escaped `$` variables, where we leave earlier `$`s.
436 fn replace_names(input: &str) -> Option<(String, HashMap<String, String>)> {
437 // Each substitution will require five or six extra bytes.
438 let mut result = String::with_capacity(input.len() + 64);
439 let mut substs = HashMap::new();
440 let mut dollar_count = 0;
441 let mut cur_name = String::new();
443 for (kind, c) in CharClasses::new(input.chars()) {
444 if kind != FullCodeCharKind::Normal {
448 } else if dollar_count == 0 {
450 } else if !c.is_alphanumeric() && !cur_name.is_empty() {
451 // Terminates a name following one or more dollars.
452 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
457 } else if c == '(' && cur_name.is_empty() {
458 // FIXME: Support macro def with repeat.
460 } else if c.is_alphanumeric() || c == '_' {
465 if !cur_name.is_empty() {
466 register_metavariable(&mut substs, &mut result, &cur_name, dollar_count);
469 debug!("replace_names `{}` {:?}", result, substs);
471 Some((result, substs))
474 #[derive(Debug, Clone)]
477 MetaVariable(ast::Ident, String),
478 /// e.g. `$($foo: expr),*`
480 /// `()`, `[]` or `{}`.
482 /// Inner arguments inside delimiters.
484 /// Something after the closing delimiter and the repeat token, if available.
485 Option<Box<ParsedMacroArg>>,
486 /// The repeat token. This could be one of `*`, `+` or `?`.
489 /// e.g. `[derive(Debug)]`
490 Delimited(DelimToken, Vec<ParsedMacroArg>),
491 /// A possible separator. e.g. `,` or `;`.
492 Separator(String, String),
493 /// Other random stuff that does not fit to other kinds.
494 /// e.g. `== foo` in `($x: expr == foo)`.
495 Other(String, String),
498 fn delim_token_to_str(
499 context: &RewriteContext,
500 delim_token: &DelimToken,
502 use_multiple_lines: bool,
503 ) -> (String, String) {
504 let (lhs, rhs) = match *delim_token {
505 DelimToken::Paren => ("(", ")"),
506 DelimToken::Bracket => ("[", "]"),
507 DelimToken::Brace => ("{ ", " }"),
508 DelimToken::NoDelim => ("", ""),
510 if use_multiple_lines {
511 let indent_str = shape.indent.to_string_with_newline(context.config);
512 let nested_indent_str = shape
514 .block_indent(context.config)
515 .to_string_with_newline(context.config);
517 format!("{}{}", lhs, nested_indent_str),
518 format!("{}{}", indent_str, rhs),
521 (lhs.to_owned(), rhs.to_owned())
526 fn starts_with_brace(&self) -> bool {
528 MacroArgKind::Repeat(DelimToken::Brace, _, _, _)
529 | MacroArgKind::Delimited(DelimToken::Brace, _) => true,
534 fn starts_with_dollar(&self) -> bool {
536 MacroArgKind::Repeat(..) | MacroArgKind::MetaVariable(..) => true,
541 fn ends_with_space(&self) -> bool {
543 MacroArgKind::Separator(..) => true,
548 fn has_meta_var(&self) -> bool {
550 MacroArgKind::MetaVariable(..) => true,
551 MacroArgKind::Repeat(_, ref args, _, _) => args.iter().any(|a| a.kind.has_meta_var()),
558 context: &RewriteContext,
560 use_multiple_lines: bool,
561 ) -> Option<String> {
562 let rewrite_delimited_inner = |delim_tok, args| -> Option<(String, String, String)> {
563 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, false);
564 let inner = wrap_macro_args(context, args, shape)?;
565 if lhs.len() + inner.len() + rhs.len() <= shape.width {
566 return Some((lhs, inner, rhs));
569 let (lhs, rhs) = delim_token_to_str(context, delim_tok, shape, true);
570 let nested_shape = shape
571 .block_indent(context.config.tab_spaces())
572 .with_max_width(context.config);
573 let inner = wrap_macro_args(context, args, nested_shape)?;
574 Some((lhs, inner, rhs))
578 MacroArgKind::MetaVariable(ty, ref name) => {
579 Some(format!("${}:{}", name, ty.name.as_str()))
581 MacroArgKind::Repeat(ref delim_tok, ref args, ref another, ref tok) => {
582 let (lhs, inner, rhs) = rewrite_delimited_inner(delim_tok, args)?;
583 let another = another
585 .and_then(|a| a.rewrite(context, shape, use_multiple_lines))
586 .unwrap_or_else(|| "".to_owned());
587 let repeat_tok = pprust::token_to_string(tok);
589 Some(format!("${}{}{}{}{}", lhs, inner, rhs, another, repeat_tok))
591 MacroArgKind::Delimited(ref delim_tok, ref args) => {
592 rewrite_delimited_inner(delim_tok, args)
593 .map(|(lhs, inner, rhs)| format!("{}{}{}", lhs, inner, rhs))
595 MacroArgKind::Separator(ref sep, ref prefix) => Some(format!("{}{} ", prefix, sep)),
596 MacroArgKind::Other(ref inner, ref prefix) => Some(format!("{}{}", prefix, inner)),
601 #[derive(Debug, Clone)]
602 struct ParsedMacroArg {
607 impl ParsedMacroArg {
610 context: &RewriteContext,
612 use_multiple_lines: bool,
613 ) -> Option<String> {
614 self.kind.rewrite(context, shape, use_multiple_lines)
618 /// Parses macro arguments on macro def.
619 struct MacroArgParser {
620 /// Holds either a name of the next metavariable, a separator or a junk.
622 /// The start position on the current buffer.
624 /// The first token of the current buffer.
626 /// Set to true if we are parsing a metavariable or a repeat.
628 /// The position of the last token.
630 /// The last token parsed.
632 /// Holds the parsed arguments.
633 result: Vec<ParsedMacroArg>,
636 fn last_tok(tt: &TokenTree) -> Token {
638 TokenTree::Token(_, ref t) => t.clone(),
639 TokenTree::Delimited(_, ref d) => d.close_token(),
643 impl MacroArgParser {
644 pub fn new() -> MacroArgParser {
650 last_tok: Token::Eof,
651 start_tok: Token::Eof,
656 fn set_last_tok(&mut self, tok: &TokenTree) {
657 self.hi = tok.span().hi();
658 self.last_tok = last_tok(tok);
661 fn add_separator(&mut self) {
662 let prefix = if self.need_space_prefix() {
667 self.result.push(ParsedMacroArg {
668 kind: MacroArgKind::Separator(self.buf.clone(), prefix),
669 span: mk_sp(self.lo, self.hi),
674 fn add_other(&mut self) {
675 let prefix = if self.need_space_prefix() {
680 self.result.push(ParsedMacroArg {
681 kind: MacroArgKind::Other(self.buf.clone(), prefix),
682 span: mk_sp(self.lo, self.hi),
687 fn add_meta_variable(&mut self, iter: &mut Cursor) -> Option<()> {
689 Some(TokenTree::Token(sp, Token::Ident(ref ident, _))) => {
690 self.result.push(ParsedMacroArg {
691 kind: MacroArgKind::MetaVariable(*ident, self.buf.clone()),
692 span: mk_sp(self.lo, sp.hi()),
696 self.is_meta_var = false;
703 fn add_delimited(&mut self, inner: Vec<ParsedMacroArg>, delim: DelimToken, span: Span) {
704 self.result.push(ParsedMacroArg {
705 kind: MacroArgKind::Delimited(delim, inner),
713 inner: Vec<ParsedMacroArg>,
718 let mut buffer = String::new();
719 let mut first = false;
720 let mut lo = span.lo();
721 let mut hi = span.hi();
723 // Parse '*', '+' or '?.
724 for ref tok in iter {
725 self.set_last_tok(tok);
728 lo = tok.span().lo();
732 TokenTree::Token(_, Token::BinOp(BinOpToken::Plus))
733 | TokenTree::Token(_, Token::Question)
734 | TokenTree::Token(_, Token::BinOp(BinOpToken::Star)) => {
737 TokenTree::Token(sp, ref t) => {
738 buffer.push_str(&pprust::token_to_string(t));
745 // There could be some random stuff between ')' and '*', '+' or '?'.
746 let another = if buffer.trim().is_empty() {
749 Some(Box::new(ParsedMacroArg {
750 kind: MacroArgKind::Other(buffer, "".to_owned()),
755 self.result.push(ParsedMacroArg {
756 kind: MacroArgKind::Repeat(delim, inner, another, self.last_tok.clone()),
757 span: mk_sp(self.lo, self.hi),
762 fn update_buffer(&mut self, lo: BytePos, t: &Token) {
763 if self.buf.is_empty() {
765 self.start_tok = t.clone();
767 let needs_space = match next_space(&self.last_tok) {
768 SpaceState::Ident => ident_like(t),
769 SpaceState::Punctuation => !ident_like(t),
770 SpaceState::Always => true,
771 SpaceState::Never => false,
773 if force_space_before(t) || needs_space {
778 self.buf.push_str(&pprust::token_to_string(t));
781 fn need_space_prefix(&self) -> bool {
782 if self.result.is_empty() {
786 let last_arg = self.result.last().unwrap();
787 if let MacroArgKind::MetaVariable(..) = last_arg.kind {
788 if ident_like(&self.start_tok) {
791 if self.start_tok == Token::Colon {
796 if force_space_before(&self.start_tok) {
803 /// Returns a collection of parsed macro def's arguments.
804 pub fn parse(mut self, tokens: ThinTokenStream) -> Option<Vec<ParsedMacroArg>> {
805 let mut iter = (tokens.into(): TokenStream).trees();
807 while let Some(ref tok) = iter.next() {
809 TokenTree::Token(sp, Token::Dollar) => {
810 // We always want to add a separator before meta variables.
811 if !self.buf.is_empty() {
812 self.add_separator();
815 // Start keeping the name of this metavariable in the buffer.
816 self.is_meta_var = true;
818 self.start_tok = Token::Dollar;
820 TokenTree::Token(_, Token::Colon) if self.is_meta_var => {
821 self.add_meta_variable(&mut iter)?;
823 TokenTree::Token(sp, ref t) => self.update_buffer(sp.lo(), t),
824 TokenTree::Delimited(sp, delimited) => {
825 if !self.buf.is_empty() {
826 if next_space(&self.last_tok) == SpaceState::Always {
827 self.add_separator();
833 // Parse the stuff inside delimiters.
834 let mut parser = MacroArgParser::new();
836 let delimited_arg = parser.parse(delimited.tts.clone())?;
838 if self.is_meta_var {
839 self.add_repeat(delimited_arg, delimited.delim, &mut iter, *sp)?;
841 self.add_delimited(delimited_arg, delimited.delim, *sp);
846 self.set_last_tok(tok);
849 // We are left with some stuff in the buffer. Since there is nothing
850 // left to separate, add this as `Other`.
851 if !self.buf.is_empty() {
860 context: &RewriteContext,
861 args: &[ParsedMacroArg],
863 ) -> Option<String> {
864 wrap_macro_args_inner(context, args, shape, false)
865 .or_else(|| wrap_macro_args_inner(context, args, shape, true))
868 fn wrap_macro_args_inner(
869 context: &RewriteContext,
870 args: &[ParsedMacroArg],
872 use_multiple_lines: bool,
873 ) -> Option<String> {
874 let mut result = String::with_capacity(128);
875 let mut iter = args.iter().peekable();
876 let indent_str = shape.indent.to_string_with_newline(context.config);
878 while let Some(ref arg) = iter.next() {
879 result.push_str(&arg.rewrite(context, shape, use_multiple_lines)?);
881 if use_multiple_lines
882 && (arg.kind.ends_with_space() || iter.peek().map_or(false, |a| a.kind.has_meta_var()))
884 if arg.kind.ends_with_space() {
887 result.push_str(&indent_str);
888 } else if let Some(ref next_arg) = iter.peek() {
889 let space_before_dollar =
890 !arg.kind.ends_with_space() && next_arg.kind.starts_with_dollar();
891 let space_before_brace = next_arg.kind.starts_with_brace();
892 if space_before_dollar || space_before_brace {
898 if !use_multiple_lines && result.len() >= shape.width {
905 // This is a bit sketchy. The token rules probably need tweaking, but it works
906 // for some common cases. I hope the basic logic is sufficient. Note that the
907 // meaning of some tokens is a bit different here from usual Rust, e.g., `*`
908 // and `(`/`)` have special meaning.
910 // We always try and format on one line.
911 // FIXME: Use multi-line when every thing does not fit on one line.
912 fn format_macro_args(
913 context: &RewriteContext,
914 toks: ThinTokenStream,
916 ) -> Option<String> {
917 let parsed_args = MacroArgParser::new().parse(toks)?;
918 wrap_macro_args(context, &parsed_args, shape)
921 // We should insert a space if the next token is a:
922 #[derive(Copy, Clone, PartialEq)]
926 Ident, // Or ident/literal-like thing.
930 fn force_space_before(tok: &Token) -> bool {
931 debug!("tok: force_space_before {:?}", tok);
952 | Token::Dollar => true,
957 fn ident_like(tok: &Token) -> bool {
959 Token::Ident(..) | Token::Literal(..) | Token::Lifetime(_) => true,
964 fn next_space(tok: &Token) -> SpaceState {
965 debug!("next_space: {:?}", tok);
969 | Token::BinOp(BinOpToken::And)
978 | Token::Question => SpaceState::Punctuation,
983 | Token::OpenDelim(_)
984 | Token::CloseDelim(_)
985 | Token::Whitespace => SpaceState::Never,
987 Token::Literal(..) | Token::Ident(..) | Token::Lifetime(_) => SpaceState::Ident,
989 _ => SpaceState::Always,
993 /// Tries to convert a macro use into a short hand try expression. Returns None
994 /// when the macro is not an instance of try! (or parsing the inner expression
996 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
997 if &format!("{}", mac.node.path) == "try" {
998 let ts: TokenStream = mac.node.tts.clone().into();
999 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1002 id: ast::NodeId::new(0), // dummy value
1003 node: ast::ExprKind::Try(parser.parse_expr().ok()?),
1004 span: mac.span, // incorrect span, but shouldn't matter too much
1005 attrs: ThinVec::new(),
1012 fn macro_style(mac: &ast::Mac, context: &RewriteContext) -> DelimToken {
1013 let snippet = context.snippet(mac.span);
1014 let paren_pos = snippet.find_uncommented("(").unwrap_or(usize::max_value());
1015 let bracket_pos = snippet.find_uncommented("[").unwrap_or(usize::max_value());
1016 let brace_pos = snippet.find_uncommented("{").unwrap_or(usize::max_value());
1018 if paren_pos < bracket_pos && paren_pos < brace_pos {
1020 } else if bracket_pos < brace_pos {
1027 /// Indent each line according to the specified `indent`.
1055 fn indent_macro_snippet(
1056 context: &RewriteContext,
1059 ) -> Option<String> {
1060 let mut lines = LineClasses::new(macro_str);
1061 let first_line = lines.next().map(|(_, s)| s.trim_right().to_owned())?;
1062 let mut trimmed_lines = Vec::with_capacity(16);
1064 let mut veto_trim = false;
1065 let min_prefix_space_width = lines
1066 .filter_map(|(kind, line)| {
1067 let mut trimmed = true;
1068 let prefix_space_width = if is_empty_line(&line) {
1071 Some(get_prefix_space_width(context, &line))
1073 let line = if veto_trim || (kind.is_string() && !line.ends_with('\\')) {
1074 veto_trim = kind.is_string() && !line.ends_with('\\');
1078 line.trim().to_owned()
1080 trimmed_lines.push((trimmed, line, prefix_space_width));
1090 |&(trimmed, ref line, prefix_space_width)| match prefix_space_width {
1091 _ if !trimmed => line.to_owned(),
1092 Some(original_indent_width) => {
1093 let new_indent_width = indent.width()
1094 + original_indent_width
1095 .checked_sub(min_prefix_space_width)
1097 let new_indent = Indent::from_width(context.config, new_indent_width);
1098 format!("{}{}", new_indent.to_string(context.config), line.trim())
1100 None => String::new(),
1103 .collect::<Vec<_>>()
1108 fn get_prefix_space_width(context: &RewriteContext, s: &str) -> usize {
1110 for c in s.chars() {
1113 '\t' => width += context.config.tab_spaces(),
1120 fn is_empty_line(s: &str) -> bool {
1121 s.is_empty() || s.chars().all(char::is_whitespace)
1124 // A very simple parser that just parses a macros 2.0 definition into its branches.
1125 // Currently we do not attempt to parse any further than that.
1127 struct MacroParser {
1132 // (`(` ... `)` `=>` `{` ... `}`)*
1133 fn parse(&mut self) -> Option<Macro> {
1134 let mut branches = vec![];
1135 while self.toks.look_ahead(1).is_some() {
1136 branches.push(self.parse_branch()?);
1139 Some(Macro { branches })
1142 // `(` ... `)` `=>` `{` ... `}`
1143 fn parse_branch(&mut self) -> Option<MacroBranch> {
1144 let tok = self.toks.next()?;
1145 let (lo, args_paren_kind) = match tok {
1146 TokenTree::Token(..) => return None,
1147 TokenTree::Delimited(sp, ref d) => (sp.lo(), d.delim),
1149 let args = tok.joint().into();
1150 match self.toks.next()? {
1151 TokenTree::Token(_, Token::FatArrow) => {}
1154 let (mut hi, body) = match self.toks.next()? {
1155 TokenTree::Token(..) => return None,
1156 TokenTree::Delimited(sp, _) => {
1157 let data = sp.data();
1160 Span::new(data.lo + BytePos(1), data.hi - BytePos(1), data.ctxt),
1164 if let Some(TokenTree::Token(sp, Token::Semi)) = self.toks.look_ahead(0) {
1169 span: mk_sp(lo, hi),
1177 // A parsed macros 2.0 macro definition.
1179 branches: Vec<MacroBranch>,
1182 // FIXME: it would be more efficient to use references to the token streams
1183 // rather than clone them, if we can make the borrowing work out.
1184 struct MacroBranch {
1186 args_paren_kind: DelimToken,
1187 args: ThinTokenStream,
1194 context: &RewriteContext,
1196 multi_branch_style: bool,
1197 ) -> Option<String> {
1198 // Only attempt to format function-like macros.
1199 if self.args_paren_kind != DelimToken::Paren {
1200 // FIXME(#1539): implement for non-sugared macros.
1205 let mut result = format_macro_args(context, self.args.clone(), shape.sub_width(5)?)?;
1207 if multi_branch_style {
1211 // The macro body is the most interesting part. It might end up as various
1212 // AST nodes, but also has special variables (e.g, `$foo`) which can't be
1213 // parsed as regular Rust code (and note that these can be escaped using
1214 // `$$`). We'll try and format like an AST node, but we'll substitute
1215 // variables for new names with the same length first.
1217 let old_body = context.snippet(self.body).trim();
1218 let (body_str, substs) = replace_names(old_body)?;
1220 let mut config = context.config.clone();
1221 config.set().hide_parse_errors(true);
1225 let has_block_body = old_body.starts_with('{');
1227 let body_indent = if has_block_body {
1230 // We'll hack the indent below, take this into account when formatting,
1231 let body_indent = shape.indent.block_indent(&config);
1232 let new_width = config.max_width() - body_indent.width();
1233 config.set().max_width(new_width);
1237 // First try to format as items, then as statements.
1238 let new_body = match ::format_snippet(&body_str, &config) {
1239 Some(new_body) => new_body,
1240 None => match ::format_code_block(&body_str, &config) {
1241 Some(new_body) => new_body,
1242 None => return None,
1245 let new_body = wrap_str(new_body, config.max_width(), shape)?;
1247 // Indent the body since it is in a block.
1248 let indent_str = body_indent.to_string(&config);
1249 let mut new_body = LineClasses::new(new_body.trim_right())
1251 (String::new(), true),
1252 |(mut s, need_indent), (kind, ref l)| {
1253 if !l.is_empty() && need_indent {
1256 (s + l + "\n", !kind.is_string() || l.ends_with('\\'))
1261 // Undo our replacement of macro variables.
1262 // FIXME: this could be *much* more efficient.
1263 for (old, new) in &substs {
1264 if old_body.find(new).is_some() {
1265 debug!("rewrite_macro_def: bailing matching variable: `{}`", new);
1268 new_body = new_body.replace(new, old);
1272 result += new_body.trim();
1273 } else if !new_body.is_empty() {
1275 result += &new_body;
1276 result += &shape.indent.to_string(&config);
1285 /// Format `lazy_static!` from https://crates.io/crates/lazy_static.
1287 /// # Expected syntax
1291 /// [pub] static ref NAME_1: TYPE_1 = EXPR_1;
1292 /// [pub] static ref NAME_2: TYPE_2 = EXPR_2;
1294 /// [pub] static ref NAME_N: TYPE_N = EXPR_N;
1297 fn format_lazy_static(context: &RewriteContext, shape: Shape, ts: &TokenStream) -> Option<String> {
1298 let mut result = String::with_capacity(1024);
1299 let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
1300 let nested_shape = shape
1301 .block_indent(context.config.tab_spaces())
1302 .with_max_width(context.config);
1304 result.push_str("lazy_static! {");
1305 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1307 macro parse_or($method:ident $(,)* $($arg:expr),* $(,)*) {
1308 match parser.$method($($arg,)*) {
1310 if parser.sess.span_diagnostic.has_errors() {
1311 parser.sess.span_diagnostic.reset_err_count();
1319 parser.sess.span_diagnostic.reset_err_count();
1325 while parser.token != Token::Eof {
1326 // Parse a `lazy_static!` item.
1327 let vis = ::utils::format_visibility(&parse_or!(parse_visibility, false));
1328 parser.eat_keyword(symbol::keywords::Static);
1329 parser.eat_keyword(symbol::keywords::Ref);
1330 let id = parse_or!(parse_ident);
1331 parser.eat(&Token::Colon);
1332 let ty = parse_or!(parse_ty);
1333 parser.eat(&Token::Eq);
1334 let expr = parse_or!(parse_expr);
1335 parser.eat(&Token::Semi);
1337 // Rewrite as a static item.
1338 let mut stmt = String::with_capacity(128);
1339 stmt.push_str(&format!(
1340 "{}static ref {}: {} =",
1343 ty.rewrite(context, nested_shape)?
1345 result.push_str(&::expr::rewrite_assign_rhs(
1349 nested_shape.sub_width(1)?,
1352 if parser.token != Token::Eof {
1353 result.push_str(&nested_shape.indent.to_string_with_newline(context.config));
1357 result.push_str(&shape.indent.to_string_with_newline(context.config));